Apparatus for forming sheet material



2 sheet-sneet 1 Oct. 11, 1932.

F. A. PARKHURT APPARATUS FOR FORMING SHEET MATERIAL Oct. l1, 1932.

- Filed Oct. l5, 1950 2 Sheets-Sheet 2 Patented Get. 11, 1932 UNITEDsrArss PATENT: OFFICE;

l FREDERIC A. PARKHUEST, E BETHEsDA, MARYLAND, Assrelvon To THEEIBEEEOID Y CORPORATION, OF INnrAN OECHAED, MASSACHUSETTS, A COEroEATroN0E MASSA- CHUSETTS ABPAEATUS EOE EOEMING SHEET MATERIAL Application siedoctober 15, i930. sern Nef easynet'.i

' 5 pyroXylin by eXtruding a mass of pyroxylin in plastic conditionunder heavy pressure through a 'narrow annular orice to form a tubewhich is slit subsequently and opened in the form of a flat Sheet. Ithas been found by practical experience with apparatus for this purposethat the Sheet produced is subject to variations in thickness andfrequenti containsminute waves which may not be apparent to the eye andd o not affect the value of the material for certain uses but whichrender it unfit for purposes where a sheet of perfect uniformity isrequired. f Y

It is vthe object of the present invention to provide an apparatus ofthistype adapted to minimize the difficulties experienced with formerapparatus and to produce a web or sheet of greater uniformity. .A Y

Before explaining in detail the present in.- vention, it is to beunderstood that the invention is not limited in its application to thedetails of construction and arrangement of parts illustrated in theaccompanying drawings, since the invention is capable' of otherembodiments and of being practiced or carried out in various ways. Also,it is to be understoodV that the phraseology or terminology employedherein is for the purpose of description and not of limitation, and itis not intended to limit the invention'beyo'nd the terms of the severalclaims hereto appended as considered in view of the prior art and therequirements thereof.

The invention will be more clearly understood from the followingdescription in conjunction with the accompanying drawings:

in which,`

Fig. 1 is a sectionaly elevational view, partly broken away, of anapparatus embodying the invention; i i

Fig. 2 is a perspective view of a portion of the apparatus; and

Figs. 8 and 4 are detail sectional views of porti ons of the apparatus.

One form of apparatus embodying the invention islillustrated in theaccompanying ferr'ed to hereinafter.

"source of power.

drawings `and comprises an extrusion press l 10 having a hollowstationary head 11 formed as a part thereof. The interior of the hollowhead`11 is provided with a threaded portion 12 adapted to receiveV abridge memberl14 held in place therein as byfa bolt 15. The bridgemember14 is provided-with a plurality Of openings` 16 connecting theinterior 'of the hollow heady llfwith the feed chamber of the press. edupon the portion 12 `and is provided with a screen 18 adapted to abutthebridgemember 14. bers 20 andV 21 is suitablyv Secured to the bridge"14. For this purpose, the membery20 is provided at one end with athreadedstem 22 adapted to Lengagethe bridge member 14 An annular frame17 is thread- A brdg-e center composed of memand is provided at itsotherend withfa j ber 21 is provided withalsocket`25 adapted to receive thefree end of va mandrel 26 Ife- An annular ring 31 isrotatably mountedV'upon the head 11byv roller bearings 32 which engage a Icollar 33lthreaded upon the head 11. A Worinwheel 85 is securedupon the ringll, asby bolts, andis adapted to engage a worm 37 rotated from any suitable Anannular disc 40 is detachably mounted upon the ring 31 as by bolts 41passing through enlarged openings'42 in the disc 40 and engaging theringl. The position of the disc`4() may be adjusted as by adjustingscrews 43 carried by the ring 31 and engaging the periphery ofthe disc.The outer surface of the ring l40'is narrowed'towards its centralopeningr to provide an ironing lip 45 forming thev'outer extremity of anannular orifice 46. An approach ringSO is secured within kthe cylinder11v adjacent the aspring member 9. Preferably,ithe"inner surface oftheapproach ring 30 and the surface of-thebridge center member 21'areyin-Vwardly in engagement withthe disc 40 as by plurality of arms 52/extending from the press 10 and suitably secured' thereto. A conicalsleeve 53 is mounted in the bearing 51 and is secured therein'byyannular rings 54 and 55 having threaded engagement with the sleeve53and abutting'opposit'e ends of 'the support 50. The mandrel 26- isrotatably supported near one end of the'sleeve 53 as by roller bearings56. A bushing 60 having a 'conical-opening 61 adapted to engage aconical surface 62 upon the mandrel 26 is threaded in the passage kinthe sleeve 53. The bushing may be held in adjusted posiltion by a bolt63 .passing through the bushing and engaging the sleeve 53. Axial move-Vvment ofthe mandrel 26 is prevented by a collar 64 threaded on themandrel and engaging an anti-friction bearing 65 abutting the outersurface of the bushing 60. A bev-el gea-r 66V is secured upon themandrel 26, as bya key 67 and is adapted to engage a pinion V68 carriedby a shaft 69 rotatably mount-ed in a bracket 7 0, secured upon one ofthe arms 52.-" The shaft 69 may be rotated from any suitable source ofpower to rotate the mandrel 2.6. l l

An annular discr 71 is heldy against a shoulder72 upon the mandrel 26 asby a collar 73 `threaded upon the freeend of the mandrel 26 which isreceived within the socketr25 iny the outer end of the bridge centermember 21. y

The outer surface of the disc 7l provides an ironing lip 74 forming theinner extremity of the orifice 46. V

' Guides 77 and 78 surround the end portion ofY the sleeve 53 adjacentthe orifice 46 and are secured thereto in spaced relation as by brackets79. A member is suitably secured near thev end of the sleeve 53 adjacentthe ori- 4lice,Y 46 and is provided with'a flange 81 eX,- tendingtoapoint adjacent the guide'77 to provide aY small orifice 82 leadingfrom a chamber 83 formed between the member 80, sleeve 53 and guide V7 7One or more Vopenings 85 are provided in the guide 7 connecting thechamber 83 with-the space between the guides 77 and 78.` A passage 86 isformed in the sleeve 53^to communicate with the chamber 83'and isconnected to a pipe 87 for supplying `fluid under pressure, such as air.Aknife is carried on a disc Vor guide91 suitably secured to the sleeve53 adjacent the guide 78,

Y as by a bracket 92. Y

v- The mandrel 26 may be adj usted longitudinally to bring the ironinglip 74 opposite the ironing lip 45 by moving the 'sleeve 53 after themandrel is centered properly therein by adjustment of the bushing 60.The ring 31 carrying the disc 40 is rotated from any suitable source ofpower through the worm 37 and worm wheel 35. The mandrel 26 is rotatedin the opposite direction at a slightly slowerl speed from any suitablesource of power through the pinion 68 and bevel gear n lastic material,such as pyroxylin 1nV 66. plastic condition, is then forced through theopenings 16 in the bridge 14 into the hollow head 11 and thence throughthe annular orilice 46 to eXtrude a thin sheet or web W in tubular form.The web W is carried over the guides 77 and 78 and at the same time airor other fluid under pressure is supplied through the pipe 87 andpassage 86 tothe chamber 83 and passes through the orifice 82 to engagewith the web W as it approaches thel guide 77. At the same time the Huidvunder pres'-Y sure passes from the chamberl 83 into the space betweenthe guides 77 and 78 topprevent the web W' frcm collapsing. The air orother fluid under pressure within the enclosure formed by the web Wbetween the guides 77 and 78 escapes between the .web and guides thuspreventing sticking of the'web thereto. After the web W passes over theguides 78 it is engaged by the knife 90 and slittedand subsequentlyopened in the form of a Hat web which is conveyed'over rolls not shown)kto a suitable drying apparatus for removing solvent from the pyroXylinweb to hardenI the same. f v I claim: f

1. An extrusion die for producing sheets from plastic materialcomprising a head having a central opening, a mandrel projecting intosaid opening, a support for said mandrel outside said head, a discmounted on saidV head having an opening surrounding saidbetween.

3. An extrusion die for producingsheets l opening surroundingsaidfmandrel andproviding an orilice therebetween.

4, An extrusion die for producing sheets from plastic materialcomprising a head having a central opening, a mandrel projecting fromplastic material comprising a head hav` ing a central opening, a mandrelprojecting projectin into said opening, one of said members ie' grotatable, and a support outside said head for said mandrel.

In testimony whereof I aix my signature. FREDERIC A. PARKHURST.

into said opening to provide a narrow annular orifice therebetweemasupport for said mandrel outside said head, said head having a hollowstationary body portion andA a disc rotatably carried thereby anddefining thev outerwall of said oriiice, an approach ring secured tosaid body portion abutting said disc, a bridge abutting said bodyportion in A spaced relationto said orifice, a bridge center extendingfrom said'bridge towards said mandrel, said bridge center and approachring having adjacent surfaces inclinedaway from said orifice. Y

6. An extrusion die for producing a web from plastic materialcomp-rising a hollow head having a central opening, a stationary supportoutside said head, a sleeve carried ,by said support having its axisaligned with j the axis of said centra-l opening, av mandrel rotatablycarried by said sleeve and project- Y ing into said opening, and meansfor centering said mandrel in said sleeve.

7. An extrusion die for producing a web from plastic material comprisinga hollow head having a central opening, a stationary support outsidesaid head having a conical bearing, a sleeve adjustably mounted in saidY bearing, and a mandrel rotatably mounted in said sleeve and projectinginto said central opening. j

8. An extrusion die for producing a web from plastic material comprisingay hollow head having a central opening, a stationary support outsidesaid head having a conical bearing, a sleeve adjustably mounted in saidbearing, a mandrel rotatably carried by said sleeve and projecting intosaid central open- ,ing said mandrel having a conical bearing portion,and-a bearing adjustably mounted in said sleeve and engaging saidconical bearg ing portion. Y

9. Ain extrusion die for producing a web `from plastic materialcomprising a hollow head having a central opening, a support Y outsidesaid head, and a mandrel ca-rried by said support and projecting intosaid opening.

10. An extrusion die for producing a web from plastic materialcomprising a hollow head having a central opening, a mandrel y 12o, y

